[Describing the effects of over-indulgence in wine:]But most too passive, when the blood runs lowToo weakly indolent to strive with pain,And bravely by resisting conquer fate,Try Circe's arts; and in the tempting bowlOf poisoned nectar sweet oblivion swill.Struck by the powerful charm, the gloom dissolvesIn empty air; Elysium opens round,A pleasing frenzy buoys the lightened soul,And sanguine hopes dispel your fleeting care;And what was difficult, and what was dire,Yields to your prowess and superior stars:The happiest you of all that e'er were mad,Or are, or shall be, could this folly last.But soon your heaven is gone: a heavier gloomShuts o'er your head; and, as the thundering stream,Swollen o'er its banks with sudden mountain rain,Sinks from its tumult to a silent brook,So, when the frantic raptures in your breastSubside, you languish into mortal man;You sleep, and waking find yourself undone,For, prodigal of life, in one rash nightYou lavished more than might support three days.A heavy morning comes; your cares returnWith tenfold rage. An anxious stomach wellMay be endured; so may the throbbing head;But such a dim delirium, such a dream,Involves you; such a dastardly despairUnmans your soul, as maddening Pentheus felt,When, baited round Citheron's cruel sides,He saw two suns, and double Thebes ascend.

Only science, exact science about human nature itself, and the most sincere approach to it by the aid of the omnipotent scientific method, will deliver man from his present gloom and will purge him from his contemporary share in the sphere of interhuman relations.

The days of my youth extend backward to the dark ages, for I was born when the rush-light, the tallow-dip or the solitary blaze of the hearth were common means of indoor lighting, and an infrequent glass bowl, raised 8 or 10 feet on a wooden post, and containing a cup full of evil-smelling train-oil with a crude cotton wick stuck in it, served to make the darkness visible out of doors. In the chambers of the great, the wax candle or, exceptionally, a multiplicity of them, relieved the gloom on state occasions, but as a rule, the common people, wanting the inducement of indoor brightness such as we enjoy, went to bed soon after sunset.

The fear of meeting the opposition of envy, or the illiberality of ignorance is, no doubt, the frequent cause of preventing many ingenious men from ushering opinions into the world which deviate from common practice. Hence for want of energy, the young idea is shackled with timidity and a useful thought is buried in the impenetrable gloom of eternal oblivion.

The mere man of pleasure is miserable in old age, and the mere drudge in business is but little better, whereas, natural philosophy, mathematical and mechanical science, are a continual source of tranquil pleasure, and in spite of the gloomy dogmas of priests and of superstition, the study of these things is the true theology; it teaches man to know and admire the Creator, for the principles of science are in the creation, and are unchangeable and of divine origin.

When you enter some grove, peopled with ancient trees, such as are higher than ordinary, and whose boughs are so closely interwoven that you cannot see the sky; the stately loftiness of the wood, the privacy of the place, and the awful gloom, cannot but strike you, as with the presence of a deity.

Epistle LXI, 'On The God Within Us', The Epistles of Lucius Annζus Seneca trans. Thomas Morell (1786), Vol. 1, 142. Also translated by Richard Mott Gummere (1916) as “If ever you come upon a grove of ancient trees which have grown to an exceptional height, shutting out a view of sky by a veil of pleached and intertwining branches, then the loftiness of the forest, the seclusion of the spot and your marvel at the thick unbroken shade in the midst of the open spaces, will prove to you the presence of deity.”

Young men, trust those certain and powerful methods, only the first secrets of which we yet know. And all of you, whatever your career, do not allow yourselves to be discouraged by the gloom of certain hours which pass a nation.

Advice in Speech (27 Dec 1892) to young scientists at the Golden Jubilee celebration for Pasteur's 70th birthday. As translated in Nature (1893), 47, 205. Also translated as Young men, have faith in those powerful and safe methods, of which we do not yet know all the secrets. And, whatever your career may be, do not let yourselves be discouraged by the sadness of certain hours which pass over nations. By Renι J. Dubos, quoted and cited in Maurice B. Strauss, Familiar Medical Quotations (1968), 526.

In science it often happens that scientists say, 'You know that's a really good argument; my position is mistaken,' and then they would actually change their minds and you never hear that old view from them again. They really do it. It doesn't happen as often as it should, because scientists are human and change is sometimes painful. But it happens every day. I cannot recall the last time something like that happened in politics or religion.
(1987) -- Carl Sagan